Frank schefold



(No Model.)

P. SCHEFOLD. MACHINE POR POLISHING GLASS.

3; A .01 6/ s .4 o O N I JV VEN' TOR NITED STATES PATENT OFFICE.

FRANK SCHEFOLD, OF NElV ALBANY, INDIANA, ASSIGNOR TO THE IV. O. DE

OF SAME PLACE.

MACHINE FOR POLISHING GLASS.

SPECIFICATION fOI'ming part 0f Letters Patent NO. 453,566, dated J une2, 1891. f

Application filed May 24, 1888. Serial No. 274,908. (No model.)

To all whom it may concern:

Be it known that I, FRANK SCHEFOLD, a citizen of the United States, anda resident of New Albany, county of Floyd, and State of Indiana, haveinvented a new and useful Improvement in Machines for Polishing Glass,of which the following is a true and exact description, due referencebeing had to the drawings which accompany and form part of thisspecification, andin which similar letters denote similar parts.

My invention consists in certain improvements in that cllaracterofpolishing-machines where the runners receive no movement independent ofthat which the rotation of the table gives them; and it consists in thefollowing: constructing the two runners of unequal size, one runnerbeing of such dimensions that its surface will extend to the outer edgeand project beyond the center of the table and the other runner being ofless size; second, by the mechanism hereinafter described causing anequal pressure to be eX- erted by the outer series of polishing-blocks,

\ and thus causing them to perform an amount of work equal to that ofthe inner polishingblocks; third, by constructing the polishingrunnersseparate from the grindingrunners and allowing them to rest unsupportedupon the glass at the commencement of polishing with the maximumpressure they will exert at any time during the polishing operation.

Where the runners are constructed of equal size and occupy a lixedposition in relation to the surface of the table there is always acertain portion of the glass on the table, at or near the center of thetable, which receives less polishing work than the portions at adistance from the center of the table; but by making one of the runnersof such diameter that it will extend to the out-er edge and projectbeyond the center of the table and the other runner of smaller diameterthe surface of the glass on the table is entirely covered and polishedequally by the runners.

It has been found in practice that the polishingrunner being supportedfrom the center the outer polishing-blocks will be held away from thesurface of the glass on the table on account of the weight of the runnerat the center tending to lift the outer surface.

I have found that if I intel-pose trusses between the center and theouter surface of the runner the weight of the runner is thrown to theouter portion, and the polishing-blocks at that point are thus forcedagainst the surface of the glass to be polished, while the innerpolishing-blocks are held againstvthe glass by their own weight. In thischaracter of polishing-machines it was formerly considered impracticableto place the polishing-runners upon the glass with the maximum pressurethey would exert at any time during the op* eration of polishing, and inpractice the polishing-runners were placed upon the surface of the glasswith a very slight pressure, which was increased as the polishingcontinued without interrupting the operation of polishing the glass.

In my improved polishing-machine I construct the polishing-miniersseparate from the grinding-runners and place them upon the surface ofthe glass with the maximum pressure which they will exert at any timeduring the operation of polishing.

In the drawings, Figure l is a plan view of the polishing-table andpolishing-runners. Fig. 2 is a vertical section of table and runners,showing method of operating the tables.

T represents the table upon which the glass to be polished is placed.This table T is given a rotary movement by the bevel-gear X Y and shaftThis movement may be given by any other wellknown means.

R represents the larger runner; R', the smaller runner. These runnersrest unsupported with their entire weight upon the table T and areretained in position by the guiderods C. The rods C have a ring at theirinner ends, which loosely surrounds the small projecting shaft G of therunners. A rod K connects the two runners. As may be seen, n.0 movementis given to the runners, with the exception of that caused by therotation of the table by which the runners rotate, and these runners areguided by the small shaft G, revolving in the ring on the end of theguides C.

A and B represent the polishing-blocks, A being the inner and B theouter. These blocks are connected to the center rim by the rods L Il,dre.

F represents the truss-rods, which project from the shaft G to the outerrim of the polishing-runners. These truss-rods are loosely bolted to therings M and N and rigidly secured to the outer ring of the runner, andin this manner, as maybe clearly seen, the Weight of the runner is'thrown to the outer surface and the outer polishing-blocks B are forcedagainst the surface of the table and the inner blocks A are held againstthe table by their own Weight, and thus both the inner and outer f setof polishing-blocks act upon the glass equally. The runner R is ofgreater diameter than the runner R and covers the sur-V face of thetable from the outer edge to a point beyond the center of the table T.

The glass to be polished, and which has previously been ground andsmoothed, is on Ythe table T, and the grinding and smoothing runnersbeing removed away from the table the polishing-runners R R, which havebeen suspended above the surface of the table by blockand tackle or an yother Well-known means, are allowed to rest unsupported upon the surfaceof the glass on the table. The means of suspension being removed and theguide-rods C and K connected to the runners, the table is caused torevolve. It Willv thus be seen that at the commencement of the pol- 30ishing operation the maximum pressure of the runners upon` the surfaceof thev glass is exerted. The revolution of the table causes the runnersto revolve on their axes, and this -movement of the table and runnerscauses the glass to be polished.

Having now fully described my improvement, What I claim, and desire toLetters Patent, is-

1. ln a glass-polishing machine, a runner having rows ofpolishing-blocks, the said polishing-runner being connected at itscenter by a truss which is rigidly connected to the exterior' of andextends to the center of said polishing-runner.

2. In a glass-polishing machine, in combination, a polishing-runnerprovided with rows of polishing-blocks, said runner being connectedtogether at its center by a truss, substantially as described, aglass-carryingtable upon which said runner rests, and' guides connectedto the center of said runner, whereby the position of the runner uponthe table is retained.

ln testimony of which invention l have hereunto set my hand, at NewAlbany, Indiana, this 16th day of May, A. D. 1888.

FRANK SCHEFOLD. Titnessesz E. B. COLLINS, VILLIAM L. TOWN.

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